# The collective dynamics of frustrated biological neuron networks

## TL;DR

This paper explores how biological neuron networks synchronize and respond to external signals, revealing how network connectivity and signal timing affect synchronization and coordination.

## Contribution

The study reveals how gap junction coupling and signal period influence synchronization and dynamic frustration in biological neuron networks.

## Key findings

- Isolated cells in a network become more synchronized with longer stimulus periods due to noise cancellation.
- Slow external signals increase gap junction coupling, which can disrupt synchronization through nonlinear bifurcations.
- Sparingly connected networks synchronize with slower signals, while highly connected ones experience dynamic frustration.

## Abstract

To maintain normal functionality, it is necessary for a multicellular organism to generate robust responses to external temporal signals. However, the underlying mechanisms to coordinate the collective dynamics of cells remain poorly understood. Here we study the calcium activity of micropatterned biological neuron networks excited by periodic ATP stimuli. Combining quantitative experiments, physical and biological manipulation of cells, as well as mathematical modeling, we show that isolated cells in a network become more synchronized at longer period of stimuli through noise cancellation. However, slowly varying external signal also increases gap junction coupling between connected nodes in the network; and gap junction mediated communication may destroy network synchronization due to special nonlinear bifurcations exhibited by the excitable dynamics of neuronal cells. Based on our results, we propose that a biological neuron network supported by gap junctional communication encodes external temporal signals in its network dynamics. A sparely connected network approaches synchronization as input signal slows down, whereas a highly connected network enters dynamic frustration in the same situation.